Diagnostic importance of urothelial cells of the dog and cat.

The cells lining the canine and feline urinary tract and their role in the diagnosis of urological diseases in small animals is assessed. The urothelium was found to consist of transitional epithelial cells ranging from the calyces to the urethra. Caudate cells were found lining the ureter, renal pelvis and the calyces. There was no feature that could be used to distinguish the transitional cells from different parts of the urothelium. Squamous cells were found lining the urinary tract from the trigone to the vagina in females and to the urethra in male animals. Hydropic degeneration in the form of vacuolation of the cytoplasm, granulation and total loss of cytoplasm was one of the urine-induced degenerative changes recorded in the transitional cells. The significance of the degenerative changes in the management of urological problems is discussed.